Taking Jinan Yellow River Bridge as an example, using 3D finite element method, displacement and behavior of four-line high-speed railway bridge with two main trusses, K-shaped brace and middle suspender is studied. The results show that transversal wave of displacement of floor system is significant, and the difference of the displacement in transversal direction reaches 6 mm. The causes includes: large distance between two main trusses, large stiffness of stringers, longitudinal stiffeners and crossbeams, weak transversal stiffeners which do not connect to lower chords. About 90% of the loads are transferred to the crossbeam through path 1 and about 60% to 80% of these loads through K-shaped braces. Less than 10% of the loads transferred to lower chords through path 2.